/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.nutch.util;

import java.util.Collection;
import java.util.Iterator;

/**
 * A class for efficiently matching <code>String</code>s against a set of
 * suffixes. Zero-length <code>Strings</code> are ignored.
 */
public class SuffixStringMatcher extends TrieStringMatcher {

	/**
	 * Creates a new <code>PrefixStringMatcher</code> which will match
	 * <code>String</code>s with any suffix in the supplied array.
	 */
	public SuffixStringMatcher(String[] suffixes) {
		super();
		for (int i = 0; i < suffixes.length; i++)
			addPatternBackward(suffixes[i]);
	}

	/**
	 * Creates a new <code>PrefixStringMatcher</code> which will match
	 * <code>String</code>s with any suffix in the supplied
	 * <code>Collection</code>
	 */
	public SuffixStringMatcher(Collection<String> suffixes) {
		super();
		Iterator<String> iter = suffixes.iterator();
		while (iter.hasNext())
			addPatternBackward(iter.next());
	}

	/**
	 * Returns true if the given <code>String</code> is matched by a suffix in
	 * the trie
	 */
	public boolean matches(String input) {
		TrieNode node = root;
		for (int i = input.length() - 1; i >= 0; i--) {
			node = node.getChild(input.charAt(i));
			if (node == null)
				return false;
			if (node.isTerminal())
				return true;
		}
		return false;
	}

	/**
	 * Returns the shortest suffix of <code>input<code> that is matched, or
	 * <code>null<code> if no match exists.
	 */
	public String shortestMatch(String input) {
		TrieNode node = root;
		for (int i = input.length() - 1; i >= 0; i--) {
			node = node.getChild(input.charAt(i));
			if (node == null)
				return null;
			if (node.isTerminal())
				return input.substring(i);
		}
		return null;
	}

	/**
	 * Returns the longest suffix of <code>input<code> that is matched, or
	 * <code>null<code> if no match exists.
	 */
	public String longestMatch(String input) {
		TrieNode node = root;
		String result = null;
		for (int i = input.length() - 1; i >= 0; i--) {
			node = node.getChild(input.charAt(i));
			if (node == null)
				break;
			if (node.isTerminal())
				result = input.substring(i);
		}
		return result;
	}

	public static final void main(String[] argv) {
		SuffixStringMatcher matcher = new SuffixStringMatcher(
				new String[] { "a", "abcd", "bcd", "bcdefg", "defg", "aac",
						"baz", "foo", "foobar" });

		String[] tests = { "a", "ac", "abcd", "abcdefg", "apple", "aa", "aac",
				"aaccca", "abaz", "baz", "bazooka", "fo", "foobar", "kite", };

		for (int i = 0; i < tests.length; i++) {
			System.out.println("testing: " + tests[i]);
			System.out.println("   matches: " + matcher.matches(tests[i]));
			System.out
					.println("  shortest: " + matcher.shortestMatch(tests[i]));
			System.out.println("   longest: " + matcher.longestMatch(tests[i]));
		}
	}
}
